The present invention relates to a fluid jetting pipe capable of changing the outlet opening area as required, and more particularly to a structure suitable for chemical jetting pipes of powered chemicals sprayers and blast jetting pipes of blow cleaners.
Fluid jetting pipes, especially jetting pipes of powered blow cleaners, are sometimes required to provide discharge jets at a relatively large air (wind) flow rate in such a case as moving a great deal of light dust at a time, and are sometimes required to provide forceful and strong discharge jets at a relatively high air pressure in such a case as blowing off stuck dust, small stones or the like. There has thus been desired a jetting pipe which is arranged to be capable of easily providing discharge jets at different air flow rates and pressures during periods of machine use dependent on working conditions and/or places. However, a conventional jetting pipe is in itself arranged not to be capable of changing the outlet opening area, i.e., to have the fixed outlet opening area. In other words, for providing discharge jets at various air flow rates and pressures, the conventional jetting pipe must be replaced with another type one, or a blower output must be adjusted on demand. This arrangement has suffered from the disadvantages that the raised air pressure would increase the useless air flow rate, and the enhanced output of the blower would increase noise.